ABSTRACT The national opioid epidemic requires development of real-world evidence based treatments for opioid use disorder, including adjuncts to Medication Assisted Treatment (MAT) with buprenorphine. Interventions are needed that address the complex needs of patients with opioid use disorder, which include substantial mental health co-morbidity and high rates of chronic pain related to the complex interaction of opioid prescribing for pain and opioid use disorder. This study leverages recent federal and state opioid use disorder treatment initiatives as a platform for testing a promising mind-body intervention, Mindful Awareness in Body-oriented Therapy (MABT) as an adjunct to MAT in two clinical settings funded through the Washington Opioid State Targeted Response (STR) program. MABT, a novel mindfulness-based intervention, uniquely addresses aspects of awareness, interoception, and regulation that may be associated with pain, mental health distress, and behavioral control that increase risk of relapse and poor treatment outcomes. Each setting employs a variation of the nationally recognized Massachusetts Nurse Care Manager model. Using a randomized, two- group, repeated measures design, we will compare those who receive MABT+ MAT to MAT only. The overarching goal of this application is to test MABT to improve MAT health outcomes among patients receiving buprenorphine to treat OUD. The specific aims for the R21 portion are to solidify partnerships with proposed clinical program sites in order to develop a plan for implementing the study intervention and procedures, and to finalize study related documents necessary for the R33, including: study protocols, data collection and informed consent forms, intervention manuals and fidelity assessment checklists, training plans for research staff, data safety and monitoring plans. The first aim for the R33 portion is to evaluate the effectiveness of MABT + MAT compared to MAT only (treatment-as-usual) in reducing opioid use (primary outcome), opioid craving, MAT discontinuation, and non-opioid drug use (secondary outcomes) at the six-month time point. Aim 2 will examine the effectiveness of MABT + MAT for improving mental health distress (i.e. depression, anxiety, somatization, emotion regulation difficulties) compared to MAT only at 6 months. Aim 3 will explore the effectiveness of MABT + MAT compared to MAT only in reducing co-morbid pain severity and interference (Brief Pain Inventory) and pain sensitivity (cold pressor test). Results of this study will inform the evidence base for behavioral treatment adjuncts to MAT with buprenorphine and directly impact the future direction of the Washington Opioid STR program.